Major technical advances have been accomplished over the past three decades in dealing with the diagnosis and correction of a variety of cardiac, pulmonary and renal defects. Despite these achievements, our therapeutic capabilities have been limited by our limited understanding of the underlying physiologic and biochemical mechanisms in disorders of these organ systems. The problems to be solved do not necessarily conform to traditional fields of training. The Program Project Grant has enabled us to organize a long-term interdisciplinary approach to the functional interrelationships involving the heart, kidneys and lungs in disorders of these organ systems. Outstanding investigators with varied backgrounds and interests have been brought together, essential research facilities have been made available, and stable salary support has been provided.